Monday, June 11, 2007
Industrial solvents known as TCE and PCE are known health hazards, but the amount of exposure that can cause harm is subject to debate.
Both are found at toxic cleanup sites. They leach into ground water and soil and can release vapors that are harmful if inhaled.
The Environmental Protection Agency describes the substances as probable carcinogens and may further reduce the amounts permitted in drinking water to less than 5 parts per billion.
Last year, the National Research Council said evidence is growing that TCE causes cancer and other illness, such as reproductive and developmental problems, impaired neurological function and autoimmune disease. The panel urged environmental regulators to act soon on a new standard. But the EPA has yet to do so.
TCE, or trichloroethylene, is used for degreasing metals. PCE, or tetrachloroethylene, is a dry-cleaning agent.
Studies link them to several cancers, developmental toxicity, endocrine effects and reproductive problems, as well as leukemia and heart, neural tube and oral cleft defects in babies.
Contamination of drinking wells years ago at North Carolina's Marine Base Camp Lejeune still reverberates in health concerns.
An environmental health professor at Boston University, Dr. Richard Clapp, said there is a strong case for linking illnesses to exposure among the Marines and their families. Clapp is a scientific expert on an advisory panel organized by federal health investigators examining the contamination there.
"The Camp Lejeune exposures were quite high, probably some the highest drinking water exposures ever seen in this country," Clapp said.
Clapp testified in 2004 for IBM employees who accused the company of exposing them to TCE and other workplace toxins.
A former Marine, Denita McCall, believes her parathyroid cancer was caused by her time at Camp Lejeune in the early 1980s. She underwent successful surgery. But at 43 with three children, she lives in fear of recurrence.
"It's a big thing to wrap your mind around," she said. "You drink water, you get sick, you die. You can't fathom that."
Cindy Cribb was stunned when three of her four children, who attended school and swam in pools at Camp Lejeune, were stricken in their 20s with illnesses never experienced in the family: non-Hodgkins lymphoma and testicular cancer, kidney cancer and unexplained internal pain and kidney problems.
"They have lost so much in life," she said. "I felt guilty for living there."
The director of Houston's Medical Center for Immune and Toxic Disorders, Dr. Andrew Campbell, said he has treated several former Camp Lejeune residents who share symptoms although they now live across the country: immune, neurological and reproductive problems, and children with unusual behavioral and processing problems.
Campbell says TCE-laced water caused a rare T-Cell lymphoma in his patient, former Navy Dr. Mike Gros. Gros, who lived and worked at the base in the 1980s, won full disability status from the Veterans Administration.
Government researchers found leukemia at twice the expected level in children whose mothers lived at the base while pregnant between 1968 and 1985, and they are investigating whether the solvents are implicated.
"At what levels they are dangerous is where a lot of the dispute lies," said Frank Bove, senior epidemiologist with the U.S. Agency for Toxic substances and Disease Registry. Research so far has focused on animals or people who inhaled the chemicals at work, not drinking water exposure.
An industry lobby, the Halogenated Solvents Industry Alliance, has questioned whether the levels of contamination and conditions at Camp Lejeune could have resulted in the illnesses blamed on the chemicals.
The group believes that the EPA's current drinking water standard sufficiently protects human health, and that strengthening it would have no measurable effect on cancer incidence, said Steve Risotto, the group's executive director.
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